Cannot ssh from outside my LAN

[mvcad]

G'day.
I had setup my work TrueNAS to automatically backup some datasets to an offsite Synology box using cron job in a scheduled task. Everything was working fine until I moved houses and My ISP sent me a new modem. Now, my TruNAS box cannot connect to my Synology box anymore. This new modem is at my place where the synology is connected to.

I have setup a DDNS service with No-IP at home and forward a port to my Synology. For some reason I can succesfully SSH from inside my LAN. however I cannot do it from outside using internet.

This is what I get when I try to SSH from outside:

This is my port forwarding in my modem.

Funny thing is that when I check the log files on my synology it say the connection was successful.

Things I have tried:

• Disable Modem Firewall
• Disable Synology Firewall
• Checked my port is not blocked by my ISP
• added these lines to ssh_config :
• ServerAliveInterval 30
  ServerAliveCountMax 5

I am lost here guys, any help would be really appreciated.

 

[Nick2253]

It sounds like you've done a really good job of troubleshooting this so far, and you've hit pretty much all of the simple fixes I can think of. At this point, I'd suggest that you need to start doing packet capture to figure out where the broken pipe is coming from.

A couple other troubleshooting things that popped into my head: can you SSH into a different machine on your network? As in, port forward to a different server and connect through to that? Also, what happens if you change the ssh port? Can you connect if you use the external IP address instead of the DDNS hostname?

 

[mvcad]

Tha

It sounds like you've done a really good job of troubleshooting this so far, and you've hit pretty much all of the simple fixes I can think of. At this point, I'd suggest that you need to start doing packet capture to figure out where the broken pipe is coming from.

A couple other troubleshooting things that popped into my head: can you SSH into a different machine on your network? As in, port forward to a different server and connect through to that? Also, what happens if you change the ssh port? Can you connect if you use the external IP address instead of the DDNS hostname?

Thanks! I kept troubleshooting as per your advice and that helped me narrow it down to the router. I already contacted the manufacturer lets hope thw best